Methods for depositing a molybdenum metal film over a dielectric surface of a substrate by a cyclical deposition process and related semiconductor device structures

ABSTRACT

Methods for depositing a molybdenum metal film over a dielectric surface of a substrate by a cyclical deposition process are disclosed. The methods may include: providing a substrate comprising a dielectric surface into a reaction chamber; depositing a nucleation film directly on the dielectric surface; and depositing a molybdenum metal film directly on the nucleation film, wherein depositing the molybdenum metal film includes: contacting the substrate with a first vapor phase reactant comprising a molybdenum halide precursor; and contacting the substrate with a second vapor phase reactant comprising a reducing agent precursor. Semiconductor device structures including a molybdenum metal film disposed over a surface of a dielectric material with an intermediate nucleation film are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 16/105,802 filed Aug. 20, 2018 titled METHODS FORDEPOSITING A MOLYBDENUM METAL FILM OVER A DIELECTRIC SURFACE OF ASUBSTRATE BY A CYCLICAL DEPOSITION PROCESS AND RELATED SEMICONDUCTORDEVICE STRUCTURES; which is a continuation-in-part of and claimspriority to U.S. patent application Ser. No. 15/691,241, filed on Aug.30, 2017, titled LAYER FORMING METHOD; which claims the benefit of U.S.Provisional Patent Application No. 62/607,070 filed Dec. 18, 2017 titledLAYER FORMING METHOD; and U.S. Provisional Patent Application No.62/619,579 filed Jan. 19, 2018 titled DEPOSITION METHOD; the disclosuresof which are hereby incorporated by reference in their entirety.

FIELD OF INVENTION

The present disclosure relates generally to methods for depositing amolybdenum metal film over a dielectric surface of a substrate andparticular methods for depositing a nucleation film directly on adielectric surface and depositing a molybdenum metal film directly onthe nucleation film. The present disclosure also general relates tosemiconductor device structures including a molybdenum metal filmdisposed directly on a nucleation film disposed directly on the surfaceof a dielectric material.

BACKGROUND OF THE DISCLOSURE

Semiconductor device fabrication processes in advanced technology nodesgenerally require state of the art deposition methods for forming metalfilms, such as, for example, tungsten metal films and copper metalfilms.

A common requisite for the deposition of a metal film is that thedeposition process is extremely conformal. For example, conformaldeposition is often required in order to uniformly deposit a metal filmover three-dimensional structures including high aspect ratio features.Another common requirement for the deposition of metal films is that thedeposition process is capable of depositing ultra-thin films which arecontinuous over a large substrate area. In the particular case whereinthe metal film is electrically conductive, the deposition process mayneed to be optimized to produce low electrical resistivity films.

Low electrical resistivity metal films commonly utilized in state of theart semiconductor device applications may include tungsten (W) and/orcopper (Cu). However, tungsten metal films and copper metal filmscommonly require a thick barrier layer, disposed between the metal filmand a dielectric material. The thick barrier layer may be utilized toprevent diffusion of metal species into the underlying dielectricmaterial thereby improving device reliability and device yield. However,the thick barrier layer commonly exhibits a high electrical resistivityand therefore results in an increase in the overall electricalresistivity of the semiconductor device structure.

Cyclical deposition processes, such as, for example, atomic layerdeposition (ALD) and cyclical chemical vapor deposition (CCVD),sequential introduce one or more precursors (reactants) into a reactionchamber wherein the precursors react with the surface of the substrateone at a time in a sequential manner. Cyclical deposition processes havebeen demonstrated which produce metal films with excellent conformalitywith atomic level thickness control.

Accordingly, methods and related device structures are desirable fordepositing and utilizing low electrical resistivity metal films whichare deposited by a conformal cyclical deposition process over adielectric material.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

In some embodiments, methods for depositing a molybdenum metal film overa dielectric surface of substrate by a cyclical deposition process areprovided. The methods may comprise: providing a substrate comprising adielectric surface into a reaction chamber; depositing a nucleation filmdirectly on the dielectric surface; and depositing a molybdenum metalfilm directly on the nucleation layer, wherein depositing the molybdenummetal film comprises: contacting the substrate with a first vapor phasereactant comprising a molybdenum halide precursor; and contacting thesubstrate with a second vapor phase reactant comprising a reducing agentprecursor.

In some embodiments, semiconductor device structures are provided. Thesemiconductor device structures may comprise: a substrate comprising adielectric surface; a nucleation film disposed directly on thedielectric surface; and a molybdenum metal film disposed directly on thenucleation film.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of theinvention, the advantages of embodiments of the disclosure may be morereadily ascertained from the description of certain examples of theembodiments of the disclosure when read in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates a non-limiting exemplary process flow, demonstratinga method for depositing a nucleation film directly on a dielectricsurface and subsequently depositing a molybdenum metal film directly onthe nucleation film according to the embodiments of the disclosure;

FIG. 2 illustrates a non-limiting exemplary process flow, demonstratinga cyclical deposition process for depositing a nucleation film directlyon a dielectric surface according to the embodiments of the disclosure;

FIG. 3 illustrates a non-limiting exemplary process flow, demonstratinga cyclical deposition process for depositing a molybdenum metal filmdirectly on a nucleation film according to the embodiments of thedisclosure;

FIGS. 4A, 4B and 4C illustrate cross-sectional schematic diagrams ofsemiconductor device structures formed during the process of depositinga nucleation film directly on a dielectric surface comprising a verticalgap feature and subsequently depositing a molybdenum metal film directlyon the nucleation film according the embodiments of the disclosure; and

FIG. 5A, 5B and 5C illustrate cross-sectional schematic diagrams ofsemiconductor device structures formed during the process of depositinga nucleation film directly on a dielectric surface comprising ahorizontal gap feature and subsequently depositing a molybdenum metalfilm directly on the nucleation film according to the embodiments of thedisclosure; and

FIG. 6 illustrates the r.m.s. surface roughness (Ra) for a molybdenummetal film deposited directly on a dielectric surface and a molybdenummetal film deposited over a dielectric surface utilizing an intermediatenucleation film according to the embodiments of the disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The illustrations presented herein are not meant to be actual views ofany particular material, structure, or device, but are merely idealizedrepresentations that are used to describe embodiments of the disclosure.

As used herein, the term “substrate” may refer to any underlyingmaterial or materials that may be used, or upon which, a device, acircuit, or a film may be formed.

As used herein, the term “cyclic deposition” may refer to the sequentialintroduction of one or more precursors (reactants) into a reactionchamber to deposit a film over a substrate and includes depositiontechniques such as atomic layer deposition and cyclical chemical vapordeposition.

As used herein, the term “cyclical chemical vapor deposition” may referto any process wherein a substrate is sequentially exposed to one ormore volatile precursors, which react and/or decompose on a substrate toproduce a desired deposition.

As used herein, the term “atomic layer deposition” (ALD) may refer to avapor deposition process in which deposition cycles, preferably aplurality of consecutive deposition cycles, are conducted in a reactionchamber. Typically, during each cycle the precursor is chemisorbed to adeposition surface (e.g., a substrate surface or a previously depositedunderlying surface such as material from a previous ALD cycle), forminga monolayer or sub-monolayer that does not readily react with additionalprecursor (i.e., a self-limiting reaction). Thereafter, if necessary, areactant (e.g., another precursor or reaction gas) may subsequently beintroduced into the process chamber for use in converting thechemisorbed precursor to the desired material on the deposition surface.Typically, this reactant is capable of further reaction with theprecursor. Further, purging steps may also be utilized during each cycleto remove excess precursor from the process chamber and/or remove excessreactant and/or reaction byproducts from the process chamber afterconversion of the chemisorbed precursor. Further, the term “atomic layerdeposition,” as used herein, is also meant to include processesdesignated by related terms such as, “chemical vapor atomic layerdeposition,” “atomic layer epitaxy” (ALE), molecular beam epitaxy (MBE),gas source MBE, or organometallic MBE, and chemical beam epitaxy whenperformed with alternating pulses of precursor composition(s), reactivegas, and purge (e.g., inert carrier) gas.

As used herein, the term “film” and “thin film” may refer to anycontinuous or non-continuous structures and material formed by themethods disclosed herein. For example, “film” and “thin film” couldinclude 2D materials, nanolaminates, nanorods, nanotubes, ornanoparticles, or even partial or full molecular layers, or partial orfull atomic layers or clusters of atoms and/or molecules. “Film” and“thin film” may comprise material or a layer with pinholes, but still beat least partially continuous.

As used herein, the term “compound material” may refer to a materialcomprising two or more different elementals chemically united.

As used herein, the term “binary compound material” may refer to amaterial consisting essentially of two different elements. Although theterm “binary compound material” may refer to a material consistingessentially of two different elementals it should be noted that thebinary compound material may also comprise trace quantities of impurityelements.

As used herein, the term “silicon binary compound material” may refer toa material consisting essentially of silicon atoms and an additionaldifferent elemental. Although the term “silicon binary compoundmaterial” may refer to a material consisting essentially of siliconatoms and an additional different elemental it should be noted that thesilicon binary compound material may also comprise trace quantities ofimpurity elements.

As used herein, the term “molybdenum binary compound material” may referto a material consisting essentially of molybdenum atoms and anadditional different elemental. Although the term “molybdenum binarycompound material” may refer to a material consisting essentially ofmolybdenum atoms and an additional different elemental it should benoted that the molybdenum binary compound material may also comprisetrace quantities of impurity elements.

As used herein, the term “molybdenum halide precursor” may refer to areactant which comprises at least a molybdenum component and a halidecomponent, wherein the halide component may include one or more of achlorine component, an iodine component, or a bromine component.

As used herein, the term “molybdenum chalcogenide halide” may refer to areactant which comprises at least a molybdenum component, a halidecomponent, and a chalcogen component, wherein a chalcogen is an elementfrom group IV of the periodic table including oxygen (O), sulphur (S),selenium (Se), and tellurium (Te).

As used herein, the term “molybdenum oxyhalide” may refer to a reactantwhich comprises at least a molybdenum component, an oxygen component,and a halide component.

As used herein, the term “reducing agent precursor” may refer to areactant that donates an electron to another species in a redox chemicalreaction.

As used herein, the term “crystalline film” may refer to a film whichdisplays at least short range ordering or even long range ordering ofthe crystalline structure and includes single crystalline films as wellas polycrystalline films.

As used herein, the term “gap feature” may refer to an opening or cavitydisposed between two surfaces of a non-planar surface. The term “gapfeature” may refer to an opening or cavity disposed between opposinginclined sidewalls of two protrusions extending vertically from thesurface of the substrate or opposing inclined sidewalls of anindentation extending vertically into the surface of the substrate, sucha gap feature may be referred to as a “vertical gap feature.” The term“gap feature” may also refer to an opening or cavity disposed betweentwo opposing substantially horizontal surfaces, the horizontal surfacesbounding the horizontal opening or cavity; such a gap feature may bereferred to as a “horizontal gap feature.”

As used herein, the term “seam” may refer to a line or one or more voidsformed by the abutment of edges formed in a gap fill metal, and the“seam” can be confirmed using a scanning transmission electronmicroscopy (STEM) or transmission electron microscopy (TEM) wherein ifobservations reveals a clear vertical line or one or more vertical voidsin a vertical gap fill metal, or a clear horizontal line or one or morehorizontal voids in a horizontal gap fill metal then a “seam” ispresent.

A number of example materials are given throughout the embodiments ofthe current disclosure, it should be noted that the chemical formulasgiven for each of the example materials should not be construed aslimiting and that the non-limiting example materials given should not belimited by a given example stoichiometry.

The present disclosure includes methods for depositing a molybdenummetal film over a surface of a dielectric material utilizing anintermediate nucleation film which is disposed directly on the surfaceof the dielectric material. Molybdenum metal thin films may be utilizedin a number of applications, such as, for example, low electricalresistivity gap-fill, liner layers for 3D-NAND, DRAM word-line features,or as an interconnect material in CMOS logic applications. The abilityto deposit a molybdenum metal film over a dielectric surface utilizingan intermediate nucleation film, i.e., without the use of a highelectrical resistivity liner layer, may allow for lower effectiveelectrical resistivity for interconnects in logic applications, i.e.,CMOS structures, and word-line/bit-line in memory applications, such as3D-NAND and DRAM structures.

Therefore, the embodiments of the disclosure may include methods fordepositing a molybdenum metal film over a dielectric surface of asubstrate utilizing an intermediate nucleation film. The methods maycomprise: providing a substrate comprising a dielectric surface into areaction chamber; depositing a nucleation film directly on thedielectric surface; and depositing a molybdenum metal film directly onthe nucleation film; wherein depositing the molybdenum metal filmcomprises: contacting the substrate with a first vapor phase reactantcomprising a molybdenum halide precursor; and contacting the substratewith a second vapor phase reactant comprising a reducing agentprecursor.

An exemplary process 100 for depositing a molybdenum metal film over adielectric surface utilizing an intermediate nucleation film isillustrated with reference to FIG. 1. The exemplary process 100 maycomprise two deposition processes, a first deposition process fordepositing the nucleation film directly on the surface of a dielectricmaterial, and a second deposition process for depositing the molybdenummetal film directly on the nucleation film.

In more detail and with reference to FIG. 1, the exemplary process 100may commence by means of a process block 110 which comprises providing asubstrate comprising a dielectric surface into a reaction chamber.

In some embodiments of the disclosure, the substrate may comprise apatterned substrate including high aspect ratio features, such as, forexample, trench structures, horizontal gaps, and/or fin structures. Forexample, the substrate may comprise one or more substantially verticalgap features and/or one or more substantially horizontal gap features.The term “gap feature” may refer to an opening or cavity disposedbetween opposing inclined sidewalls of two protrusions extendingvertically from the surface of the substrate or opposing inclinedsidewalls of an indentation extending vertically into the surface of thesubstrate, such a gap feature may be referred to as a “vertical gapfeature.” The term “gap feature” may also refer to an opening or cavitydisposed between two opposing substantially horizontal surfaces, thehorizontal surfaces bounding the horizontal opening or cavity; such agap feature may be referred to as a “horizontal gap feature.” It shouldbe noted that the embodiments of the disclosure are not limited tofilling vertical gap features and/or horizontal gap features and thatother geometries of gap features disposed in and/or on a substrate maybe filled with a molybdenum metal by the processes disclosed herein.

In some embodiments of the disclosure, the substrate may comprise one ormore substantially vertical gap features as illustrated in FIG. 4A whichdemonstrates semiconductor device structure 400 including substrate 402comprising a dielectric material with a high aspect ratio vertical gapfeature 404 disposed in the substrate 402. In some embodiments, the oneor more vertical gap features may have an aspect ratio (height:width)which may be greater than 2:1, or greater than 5:1, or greater than10:1, or greater than 25:1, or greater than 50:1, or even greater than100:1, wherein “greater than” as used in this example refers to agreater distance in the height of the gap feature.

In some embodiments of the disclosure, the substrate may comprise one ormore substantially horizontal gap features as illustrated in FIG. 5Awhich demonstrates semiconductor device structure 500 includingsubstrate 502 comprising a dielectric material with a high aspect ratiohorizontal gap feature 504 disposed in the substrate 502. In someembodiments, the one or more horizontal gap features may have an aspectratio (height:width) which may be greater than 1:2, or greater than 1:5,or greater than 1:10, or greater than 1:25, or greater than 1:50, oreven greater than 1:100, wherein “greater than” as used in this examplerefers to a greater distance in the width of the gap feature.

The substrate may comprise one or more materials and material surfacesincluding, but not limited to, semiconductor materials, dielectricmaterials, and metallic materials.

In some embodiments, the substrate may include semiconductor materials,such as, but not limited to, silicon (Si), germanium (Ge), germanium tin(GeSn), silicon germanium (SiGe), silicon germanium tin (SiGeSn),silicon carbide (SiC), or a group III-V semiconductor materials.

In some embodiments, the substrate may include metallic materials, suchas, but not limited to, pure metals, metal nitrides, metal carbides,metal borides, and mixtures thereof.

In some embodiments, the substrate may include dielectric materials,such as, but not limited, to silicon containing dielectric materials andmetal oxide dielectric materials. In some embodiments, the substrate maycomprise one or more dielectric surfaces comprising a silicon containingdielectric material such as, but not limited to, silicon dioxide (SiO₂),silicon sub-oxides, silicon nitride (Si₃N₄), silicon oxynitride (SiON),silicon oxycarbide (SiOC), silicon oxycarbide nitride (SiOCN), siliconcarbon nitride (SiCN). In some embodiments, the substrate may compriseone or more dielectric surfaces comprising a metal oxide such as, butnot limited to, aluminum oxide (Al₂O₃), hafnium oxide (HfO₂), tantalumoxide (Ta₂O₅), zirconium oxide (ZrO₂), titanium oxide (TiO₂), hafniumsilicate (HfSiO_(x)), and lanthanum oxide (La₂O₃).

In some embodiments of the disclosure, the substrate may comprise anengineered substrate wherein a surface semiconductor layer is disposedover a bulk support with an intervening buried oxide (BOX) disposedthere between.

Patterned substrates may comprise substrates that may includesemiconductor device structures formed into or onto a surface of thesubstrate, for example, a patterned substrate may comprise fabricatedand/or partially fabricated semiconductor device structures, such as,for example, transistors and/or memory elements. In some embodiments,the substrate may contain monocrystalline surfaces and/or one or moresecondary surfaces that may comprise a non-monocrystalline surface, suchas a polycrystalline surface and/or an amorphous surface.Monocrystalline surfaces may comprise, for example, one or more ofsilicon (Si), silicon germanium (SiGe), germanium tin (GeSn), orgermanium (Ge). Polycrystalline or amorphous surfaces may includedielectric materials, such as oxides, oxynitrides, oxycarbides,oxycarbide nitrides, nitrides, or mixtures thereof.

The substrate may be disposed into one or more reaction chambersconfigured for depositing the nucleation film directly on the surface ofa dielectric material and for depositing a molybdenum metal filmdirectly on the nucleation film. In some embodiments, the nucleationfilm may be deposited directly on a dielectric surface by one or more ofa chemical vapor deposition (CVD) process, a soak process, aplasma-enhanced chemical vapor deposition (PECVD) process, or a physicalvapor deposition (PVD) process. In particular embodiments of thedisclosure, the nucleation film and the molybdenum film may both bedeposited utilizing cyclical deposition processes due to the inherentconformality achievable utilizing cyclical deposition processes and theability of cyclical deposition processes to form conformal films overnon-planar substrates comprising one or more high aspect ratio features,including, but not limited to, vertical gap features and/or horizontalgap features.

Therefore, reactors or reaction chamber capable of being used to deposita molybdenum metal film over a dielectric surface utilizing anintermediate nucleation film may be configured for performing cyclicaldeposition processes, such as, for example, atomic layer depositionprocesses or cyclical chemical vapor deposition processes. Thereforereactors or reaction chambers suitable for performing the embodiments ofthe disclosure may include ALD reactors, as well as CVD reactors,configured to provide the precursors. According to some embodiments, ashowerhead reactor may be used. According to some embodiments,cross-flow, batch, minibatch, or spatial ALD reactors may be used.

In some embodiments of the disclosure, a batch reactor may be used. Insome embodiments, a vertical batch reactor may be used. In otherembodiments, a batch reactor comprises a minibatch reactor configured toaccommodate 10 or fewer wafers, 8 or fewer wafers, 6 or fewer wafers, 4or fewer wafers, or 2 or fewer wafers. In some embodiments in which abatch reactor is used, wafer-to-wafer non-uniformity is less than 3% (1sigma), less than 2%, less than 1%, or even less than 0.5%.

The exemplary processes for depositing a molybdenum metal film fillutilizing an intermediate nucleation film as described herein mayoptionally be carried out in a reactor(s) or reaction chamber(s)connected to a cluster tool. In a cluster tool, because each reactionchamber is dedicated to one type of process, the temperature of thereaction chamber in each module can be kept constant, which improves thethroughput compared to a reactor in which the substrate is heated up tothe process temperature before each run. Additionally, in a cluster toolit is possible to reduce the time to pump the reaction chamber to thedesired process pressure levels between substrates. In some embodimentsof the disclosure, the exemplary processes disclosed herein may beperformed in a cluster tool comprising multiple reaction chambers,wherein each individual reaction chamber may be utilized to expose thesubstrate to an individual precursor gas and the substrate may betransferred between different reaction chambers for exposure to multipleprecursors gases, the transfer of the substrate being performed under acontrolled ambient to prevent oxidation/contamination of the substrate.For example, the deposition of the nucleation film may be performed by acyclical deposition process in a first reaction chamber associated witha cluster tool and the deposition of the molybdenum film may beperformed by a cyclical deposition process in a second reaction chamberassociated with the same cluster tool with the transfer between thefirst reaction chamber and the second reaction chamber taking placeunder a controlled environment to prevent contamination or degradationof the substrate and associated films. In some embodiments of thedisclosure, the processes of the current disclosure may be performed ina cluster tool comprising multiple reaction chambers, wherein eachindividual reaction chamber may be configured to heat the substrate to adifferent temperature.

In some embodiments, the exemplary process of depositing a nucleationfilm directly on a dielectric surface and depositing a molybdenum metalfilm directly on the nucleation film may be performed in a singlestand-alone reactor which may be equipped with a load-lock. In thatcase, it is not necessary to cool down the reaction chamber between eachrun.

Once the substrate is deposited within a suitable reaction chamber,e.g., a reaction chamber configured for cyclical deposition processes,the exemplary process 100 of FIG. 1 may proceed by means of a processblock 120 comprising deposing a nucleation film directly on a dielectricsurface. The process block 120 and it constituent sub-processes aredescribed in more detail with reference to FIG. 2 which illustrates anexemplary non-limiting cyclical deposition process for depositing anucleation film directly on a dielectric surface.

In more detail, the deposition process for depositing the nucleationfilm directly on the dielectric surface may proceed by means of asub-process 210 comprising heating the substrate to a desired depositiontemperature. For example, the substrate may be heated to a substratetemperature of less than approximately 800° C., or less thanapproximately 700° C., or less than approximately 600° C., or less thanapproximately 500° C., or less than approximately 400° C., or less thanapproximately 300° C., or even less than approximately 200° C. In someembodiments of the disclosure, the substrate temperature during thecyclical deposition process of process block 120 may be between 250° C.and 800° C., or between 300° C. and 600° C., or between 550° C. and 600°C.

In some embodiments, the deposition temperature for depositing thenucleation film may be dependent on the composition of the materialbeing deposited. For example, in some embodiments of the disclosure, thenucleation film may comprise a compound material, i.e., a materialcomprising at least two different elements. In some embodiments, thecompound material may comprise a binary compound material, i.e., amaterial consisting essentially of two different elements and tracequantities of impurity elements. In some embodiments, the compound maycomprise a ternary compound material, i.e., a material consistingessentially of three different elements and trace quantities of impurityelements.

In some embodiments, the binary compound material may comprise a siliconbinary compound material, wherein a silicon compound material consistsessentially of silicon atoms and a different element with tracequantities of impurity elements. For example, in some embodiments, asilicon binary compound material may comprise at least of a siliconnitride (e.g., Si₃N₄), a silicon carbide (e.g., SiC), or a silicon oxide(e.g., SiO₂). In such example embodiments, the temperature of thesubstrate during deposition of the nucleation layer comprising a siliconbinary compound material may be less than approximately 500° C., or lessthan approximately 400° C., or less than approximately 300° C., or lessthan approximately 250° C., or even less than approximately 200° C.

In some embodiments, the binary compound material may comprise amolybdenum binary compound material, wherein a molybdenum compoundmaterial consists essentially of molybdenum atoms and a differentelement with trace quantities of impurity elements. For example, in someembodiments, a molybdenum binary compound material may comprise at leastone of a molybdenum nitride, a molybdenum carbide, a molybdenum oxide,or a molybdenum silicide. In such example embodiments, the temperatureof the substrate during deposition of the nucleation film comprising amolybdenum binary compound material may be less than approximately 700°C., or less than approximately 600° C., or less than approximately 500°C., or less than approximately 400° C., or even less than approximately300° C. In some embodiments, the deposition of the nucleation filmcomprising a molybdenum binary compound material may be performed at asubstrate temperature between 300° C. and 600° C., or between 400° C.and 500° C.

In some embodiments of the disclosure, the nucleation film may comprisea ternary compound, such as, for example, a silicon ternary compound(e.g., SiCN, SiON), or a molybdenum ternary compound (e.g., MoON,MoSiO). In such embodiments, the temperature of substrate during thedeposition of the ternary compound may less than approximately 700° C.,or less than approximately 600° C., or less than approximately 500° C.,or less than approximately 400° C., or even less than approximately 300°C.

In addition, to achieving a desired deposition temperature, i.e., adesired substrate temperature, the exemplary atomic layer depositionprocess for depositing a nucleation film directly on a dielectricsurface (i.e., process block 120) may also regulate the pressure withinthe reaction chamber during the deposition to obtain desirablecharacteristics of the nucleation film directly on the dielectricsurface. For example, in some embodiments of the disclosure, theexemplary cyclical deposition process may be performed within a reactionchamber regulated to a reaction chamber pressure of less than 300 Torr,or less than 200 Torr, or less than 100 Torr, or less than 50 Torr, orless than 25 Torr, or less than 15 Torr, or even less than 1 Torr. Insome embodiments, the pressure within the reaction chamber duringdeposition of the nucleation film may be regulated at a pressure between1 Torr and 300 Torr, or between 1 Torr and 50 Torr, or between 1 Torrand 15 Torr, or even equal to or greater than 30 Torr.

Once the substrate has been heated to a desired temperature and thepressure within the reaction chamber has been regulated to a desiredlevel the exemplary process for depositing the nucleation film directlyon a dielectric surface may continue by means of a cyclical depositionphase 205 which may comprise an atomic layer deposition (ALD) a orcyclical chemical vapor deposition (CCVD).

A non-limiting example embodiment of a cyclical deposition process mayinclude atomic layer deposition (ALD), wherein ALD is based on typicallyself-limiting reactions, whereby sequential and alternating pulses ofreactants are used to deposit about one atomic (or molecular) monolayerof material per deposition cycle. The deposition conditions andprecursors are typically selected to provide self-saturating reactions,such that an absorbed layer of one reactant leaves a surface terminationthat is non-reactive with the gas phase reactants of the same reactants.The substrate is subsequently contacted with a different reactant thatreacts with the previous termination to enable continued deposition.Thus, each cycle of alternated pulses typically leaves no more thanabout one monolayer of the desired material. However, as mentionedabove, the skilled artisan will recognize that in one or more ALD cyclesmore than one monolayer of material may be deposited, for example, ifsome gas phase reactions occur despite the alternating nature of theprocess.

In an ALD-type process utilized for the formation of a nucleation filmdirectly on a dielectric surface one deposition cycle may compriseexposing the substrate to a first vapor phase reactant, removing anyunreacted first reactant and reaction byproducts from the reactionchamber, and exposing the substrate to a second vapor phase reactant,followed by a second removal step. In some embodiments of thedisclosure, the first vapor phase reactant may comprise at least one ofa first silicon precursor or a molybdenum precursor and the second vaporphase reactant may comprise at least one of a nitrogen precursor, acarbon precursor, an oxygen precursor, or a second silicon precursor.

Precursors may be separated by inert gases, such as argon (Ar) ornitrogen (N₂), to prevent gas-phase reactions between reactants andenable self-saturating surface reactions. In some embodiments, however,the substrate may be moved to separately contact a first vapor phasereactant and a second vapor phase reactant. Because the reactionsself-saturate, strict temperature control of the substrates and precisedosage control of the precursors may not be required. However, thesubstrate temperature is preferably such that an incident gas speciesdoes not condense into monolayers nor decompose on the surface. Surpluschemicals and reaction byproducts, if any, are removed from thesubstrate surface, such as by purging the reaction space or by movingthe substrate, before the substrate is contacted with the next reactivechemical. Undesired gaseous molecules can be effectively expelled from areaction space with the help of an inert purging gas. A vacuum pump maybe used to assist in the purging.

According to some non-limiting embodiments of the disclosure, ALDprocesses may be used to deposit a nucleation film directly on adielectric material surface. In some embodiments of the disclosure, eachALD cycle may comprise two distinct deposition steps or stages. In afirst stage of the deposition cycle the substrate surface on whichdeposition is desired may be contacted with a first vapor phase reactantcomprising at least one of first silicon precursor or a molybdenumprecursor which chemisorbs on to the surface of the substrate, formingno more than about one monolayer of reactant species on the surface ofthe substrate. In a second stage of the deposition the substrate surfaceon which deposition is desired may be contacted with a second vaporphase reactant comprising at least one of a nitrogen precursor, a carbonprecursor, an oxygen precursor, or a second silicon precursor.

Upon heating the substrate to a desired deposition temperature andregulating the pressure within the reaction chamber, the exemplaryatomic layer deposition process 120 may continue with a cyclicaldeposition phase 205 by means of a process block 220, which comprisescontacting the substrate with a first vapor phase reactant andparticularly, in some embodiments, contacting the substrate with a firstvapor phase reactant comprising at least one of a first siliconprecursor or a molybdenum halide precursor.

In some embodiments, the nucleation film may comprise a silicon binarycompound and in such embodiments the first vapor phase reactant maycomprise a first silicon precursor. In some embodiments, the firstsilicon precursor may comprise at least one of silanediamineN,N,N′,N-tetraethyl (C₈H₂₂N₂Si), BTBAS (bis(tertiarybutylamino)silane),BDEAS (bis(diethylamino)silane), TDMAS (tris(dimethylamino)silane),hexakis(ethylamino)disilane (Si₂(NHC₂H₅)₆), silicon tetraiodide (SiI₄),silicon tetrachloride (SiCl₄), hexachlorodisilane (HCDS), orpentachlorodisilane(PCDS). In some embodiments, the first siliconprecursor may comprise a silane, such as, for example, silane (SiH₄),disilane (Si₂H₆), trisilane (Si₃H₈), tetrasilane (Si₄H₁₀) or higherorder silanes with the general empirical formula Si_(x)H_((2x+2)).

In some embodiments, the nucleation film may comprise a molybdenumbinary compound and in such embodiments the first vapor phase reactantmay comprise a molybdenum halide precursor. In some embodiments, themolybdenum halide precursor may comprise a molybdenum chlorideprecursor, a molybdenum iodide precursor, or a molybdenum bromideprecursor. For example, as a non-limiting example, the first vapor phasereactant may comprise a molybdenum chloride, such as, for example,molybdenum pentachloride (MoCl₅).

In some embodiments, the molybdenum halide precursor may comprise amolybdenum chalcogenide and in particular embodiments the molybdenumhalide precursor may comprise a molybdenum chalcogenide halide. Forexample, the molybdenum chalcogenide halide precursor may comprise amolybdenum oxyhalide selected from the group comprising: a molybdenumoxychloride, a molybdenum oxyiodide, or a molybdenum oxybromide. Inparticular embodiments of the disclosure, the molybdenum precursor maycomprise a molybdenum oxychloride, including, but not limited to,molybdenum (IV) dichloride dioxide (MoO₂Cl₂).

In some embodiments of the disclosure, contacting the substrate with afirst vapor phase reactant comprising at least a first silicon precursoror a molybdenum precursor may comprise contacting the first vapor phasereactant to the substrate for a time period of between about 0.1 secondsand about 60 seconds, between about 0.1 seconds and about 10 seconds, orbetween about 0.5 seconds and about 5.0 seconds. In addition, during thecontacting of the substrate with the first vapor phase reactant, theflow rate of the precursor may be less than 1000 sccm, or less than 500sccm, or less than 100 sccm, or less than 10 sccm, or even less than 1sccm. In addition, during the contacting of substrate with the firstvapor phase reactant the flow rate of the precursor may range from about1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500sccm.

The exemplary atomic layer deposition process for deposition anucleation film directly on a dielectric surface as illustrated byprocess block 120 of FIG. 2 may continue by purging the reactionchamber. For example, excess first vapor phase reactant and reactionbyproducts (if any) may be removed from the surface of the substrate,e.g., by pumping with an inert gas. In some embodiments of thedisclosure, the purge process may comprise a purge cycle wherein thesubstrate surface is purged for a time period of less than approximately5.0 seconds, or less than approximately 3.0 seconds, or even less thanapproximately 2.0 seconds. Excess first vapor phase reactant, such as,for example, excess first silicon precursor or molybdenum precursor andany possible reaction byproducts may be removed with the aid of avacuum, generated by a pumping system in fluid communication with thereaction chamber.

Upon purging the reaction chamber with a purge cycle the exemplaryatomic layer deposition process block 120 may continue with a secondstage of the cyclical deposition phase 205 by means of a process block230 which comprises contacting the substrate with a second vapor phasereactant, and particularly contacting the substrate with a second vaporphase reactant comprising at least one of a nitrogen precursor, a carbonprecursor, an oxygen precursor, or a second silicon precursor.

In some embodiments of the disclosure, the nucleation film may comprisea silicon binary compound material and in particular embodimentscomprises a silicon nitride (e.g., Si₃N₄). In such embodiments, thefirst vapor phase reactant may comprise a first silicon precursor andthe second vapor phase reactant may comprise a nitrogen precursor.

In some embodiments of the disclosure, the nucleation film may comprisea silicon binary compound material and in particular embodimentscomprises a silicon oxide (e.g., SiO₂). In such embodiments, the firstvapor phase reactant may comprise a first silicon precursor and thesecond vapor phase reactant may comprise an oxygen precursor.

In some embodiments of the disclosure, the nucleation film may comprisea silicon binary compound material and in particular embodimentscomprises a silicon carbide (e.g., SiC). In such embodiments, the firstvapor phase reactant may comprise a first silicon precursor and thesecond vapor phase reactant may comprise a carbon precursor.

In some embodiments of the disclosure, the nucleation film may comprisea molybdenum binary compound material and in particular embodimentscomprises a molybdenum nitride. In such embodiments, the first vaporphase reactant may comprise a molybdenum precursor and the second vaporphase reactant may comprise a nitrogen precursor.

In some embodiments of the disclosure, the nucleation film may comprisea molybdenum binary compound material and in particular embodimentscomprises a molybdenum oxide. In such embodiments, the first vapor phasereactant may comprise a molybdenum precursor and the second vapor phasereactant may comprise an oxygen precursor.

In some embodiments of the disclosure, the nucleation film may comprisea molybdenum binary compound material and in particular embodimentscomprises a molybdenum silicide. In such embodiments, the first vaporphase reactant may comprise a molybdenum precursor and the second vaporphase reactant may comprise a second silicon precursor.

In some embodiments of the disclosure, the nucleation film may comprisea molybdenum binary compound material and in particular embodimentscomprises a molybdenum carbide. In such embodiments, the first vaporphase reactant may comprise a molybdenum precursor and the second vaporphase reactant may comprise a carbon precursor.

In embodiments wherein the nucleation film comprises a nitride, such as,for example, a silicon nitride or a molybdenum nitride, the second vaporphase reactant may comprise a nitrogen precursor. In such embodiments ofthe disclosure, the nitrogen precursor may comprise at least one ofammonia (NH₃), hydrazine (N₂H₄), triazane (N₃H₅), tertbutylhydrazine(C₄H₉N₂H₃), methylhydrazine (CH₃NHNH₂), dimethylhydrazine ((CH₃)₂N₂H₂),or a nitrogen plasma, wherein a nitrogen plasma includes atomicnitrogen, nitrogen radicals and excited nitrogen species.

In embodiments wherein the nucleation film comprises an oxide, such as,for example, a silicon oxide or a molybdenum oxide, the second vaporphase reactant may comprise an oxygen precursor. In such embodiments ofthe disclosure, the oxygen precursor comprises at least one of water(H₂O), hydrogen peroxide (H₂O₂), ozone (O₃), or oxides of nitrogen, suchas, for example, nitrogen monoxide (NO), nitrous oxide (N₂O), ornitrogen dioxide (NO₂). In some embodiments of the disclosure, theoxygen precursor may comprise an organic alcohol, such as, for example,isopropyl alcohol. In some embodiments, the oxygen precursor maycomprise an oxygen plasma, wherein an oxygen plasma comprises atomicoxygen, oxygen radicals, and excited oxygen species.

In embodiments wherein the nucleation film comprises a carbide, such as,for example, a silicon carbide or a molybdenum carbide, the second vaporphase reactant may comprise a carbon precursor. In such embodiments ofthe disclosure, the carbon precursor may comprise a hydrocarbon, suchas, for example, linear or branched alkanes.

In embodiments wherein the nucleation film comprises a silicide, suchas, for example, a molybdenum silicide, the second vapor phase reactantmay comprise a second silicon precursor. In such embodiments of thedisclosure, the second silicon precursor comprises at least one ofsilanediamine N,N,N′,N-tetraethyl (C₈H₂₂N₂Si), BTBAS(bis(tertiarybutylamino)silane), BDEAS (bis(diethylamino)silane), TDMAS(tris(dimethylamino)silane), hexakis(ethylamino)disilane (Si₂(NHC₂H₅)₆),silicon tetraiodide (SiI₄), silicon tetrachloride (SiCl₄),hexachlorodisilane (HCDS), or pentachlorodisilane(PCDS). In someembodiments, the second silicon precursor may comprise a silane, suchas, for example, silane (SiH₄), disilane (Si₂H₆), trisilane (Si₃H₈),tetrasilane (Si₄H₁₀) or higher order silanes with the general empiricalformula Si_(x)H_((2x+2)).

In some embodiments of the disclosure, contacting the substrate with thesecond vapor phase reactant may comprise contacting the substrate withthe precursor for a time period of between about 0.01 seconds and about120 seconds, between about 0.05 seconds and about 60 seconds, or betweenabout 0.1 seconds and about 10 seconds. In addition, during thecontacting of the substrate with the second vapor phase reactant, theflow rate of the second vapor phase reactant may be less than 10000sccm, or less than 5000× sccm, or even less than 1000×.

Upon contacting the substrate with the second vapor phase reactantcomprising at least one of nitrogen precursor, a carbon precursor, anoxygen precursor, or a second silicon precursor, the exemplary processblock 120 for depositing a nucleation film directly on a dielectricsurface may proceed by purging the reaction chamber. For example, excesssecond vapor phase reactant and reaction byproducts (if any) may beremoved from the surface of the substrate, e.g., by pumping whilstflowing an inert gas. In some embodiments of the disclosure, the purgeprocess may comprise purging the substrate surface for a time period ofbetween approximately 0.1 seconds and approximately 10 seconds, orbetween approximately 0.5 seconds and approximately 3 seconds, or evenbetween approximately 1 second and 2 seconds.

Upon completion of the purge of the second vapor phase reactant and anyreaction byproducts from the reaction chamber, the cyclic depositionphase 205 of exemplary atomic layer deposition of process block 120 maycontinue with a decision gate 240, wherein the decision gate 240 isdependent on the thickness of the nucleation film deposited. Forexample, if the nucleation film is deposited at an insufficientthickness for a desired device application, then the cyclical depositionphase 205 may be repeated by returning to the process block 220 andcontinuing through a further deposition cycle, wherein a unit depositioncycle may comprise contacting the substrate with at least a firstsilicon precursor or a molybdenum halide precursor (process block 220),purging the reaction chamber, contacting the substrate with at least oneof a nitrogen precursor, a carbon precursor, an oxygen precursor, or asecond silicon precursor (process block 230), and again purging thereaction chamber. A unit deposition cycle of cyclical deposition phase205 may be repeated one or more times until a desired thickness of anucleation film is deposited over the substrate and particularlydirectly on a dielectric surface. Once the nucleation film has beendeposited to the desired thickness the exemplary atomic layer depositionprocess block 120 may exit via a process block 250 and the substratecomprising a dielectric surface, with the nucleation film depositedthereon, may be subjected to the further processes of exemplary process100 of FIG. 1.

It should be appreciated that in some embodiments of the disclosure, theorder of contacting of the substrate with the first vapor phase reactant(e.g., the first silicon precursor or the molybdenum precursor) and thesecond vapor phase reactant (e.g., the nitrogen precursor, a carbonprecursor, an oxygen precursor, or a second silicon precursor) may besuch that the substrate is first contacted with the second vapor phasereactant followed by the first vapor phase reactant. In addition, insome embodiments, the cyclical deposition phase 205 of exemplary processblock 120 may comprise contacting the substrate with the first vaporphase reactant one or more times prior to contacting the substrate withthe second vapor phase reactant one or more times. In addition, in someembodiments, the cyclical deposition phase 205 of exemplary processblock 120 may comprise contacting the substrate with the second vaporphase reactant one or more times prior to contacting the substrate withthe first vapor phase reactant one or more times.

In some embodiments the cyclical deposition process may be a hybridALD/CVD or a cyclical CVD process. For example, in some embodiments, thegrowth rate of the ALD process may be low compared with a CVD process.One approach to increase the growth rate may be that of operating at ahigher substrate temperature than that typically employed in an ALDprocess, resulting in some portion of a chemical vapor depositionprocess, but still taking advantage of the sequential introduction ofprecursors, such a process may be referred to as cyclical CVD. In someembodiments, a cyclical CVD process may comprise the introduction of twoor more precursors into the reaction chamber wherein there may be a timeperiod of overlap between the two or more precursors in the reactionchamber resulting in both an ALD component of the deposition and a CVDcomponent of the deposition. For example, a cyclical CVD process maycomprise the continuous flow of a one precursor and the periodic pulsingof a second precursor into the reaction chamber.

In some embodiments of the disclosure, the nucleation film may bedeposited directly on a dielectric surface at a growth rate from about0.05 Å/cycle to about 5 Å/cycle, from about 0.1 Å/cycle to about 5Å/cycle, or even from about 0.5 Å/cycle to about 1.5 Å/cycle.

In some embodiments of the disclosure, the nucleation film is depositedas a continuous film, see for example the semiconductor device structure405 which includes the continuous nucleation film 406 disposed directlyon a dielectric substrate 402 comprising a vertical gap feature 404, asillustrated in FIG. 4B, or see for example the semiconductor devicestructure 505 comprising the continuous nucleation film 506 disposeddirectly on a dielectric substrate 502 comprising a horizontal gapfeatures, as illustrated in FIG. 5B. In some embodiments, the continuousnucleation film 406/506 may be deposited to a thickness of less than 20Angstroms, or less than 10 Angstroms, or less than 5 Angstroms, or evenless than 3 Angstroms.

In some embodiments of the disclosure, the nucleation film is depositedas a discontinuous film, see for example the insert of 408 ofsemiconductor device structure 405 which includes an example of adiscontinuous nucleation film 406′ disposed directly on a dielectricsubstrate 402 comprising a vertical gap feature 404, as illustrated inFIG. 4B, or see for example the insert 508 of semiconductor devicestructure 505 which include an example of a discontinuous nucleationfilm 506′ disposed directly on a dielectric substrate 502 comprising ahorizontal gap features, as illustrated in FIG. 5B. In some embodiments,the discontinuous nucleation film 406′/506′ may be deposited to athickness of less than 20 Angstroms, or less than 10 Angstroms, or lessthan 5 Angstroms, or even less than 3 Angstroms.

In some embodiments, the step coverage of the nucleation film over oneor more dielectric gap features may be equal to or greater than about50%, or greater than about 80%, or greater than about 90%, or greaterthan about 95%, or greater than about 98%, or about 99% or greater.

It should also be noted that the nucleation films of the currentdisclosure do not constitute a barrier layer or barrier material ascommonly used in semiconductor device applications to prevent diffusionof metal species into an underlying dielectric material, the barrierlayer being disposed between a metal contact and the dielectricmaterial. The nucleation films of the current disclosure are utilized toimprove the material qualities of a subsequently deposited molybdenummetal film and do not constitute the thick film, high resistivitybarrier layers or barrier materials utilized in common semiconductordevice fabrication processes.

Upon depositing the nucleation film directly on dielectric surface theexemplary process 100 (of FIG. 1) may continue by means of a processblock 130 comprising depositing a molybdenum metal film directly on thenucleation film and in some particular embodiments depositing themolybdenum metal film directly on the nucleation film by a cyclicaldeposition process. The process block 130 and the related constituentsub-process blocks are described in greater detail with reference toFIG. 3, which illustrated an exemplary cyclical deposition process fordepositing the molybdenum metal film.

In more detail, the exemplary cyclical deposition process may comprisean atomic layer deposition process or a cyclical chemical vapordeposition process. As a non-limiting example, the process block 130 maycomprise an atomic layer deposition process and may commence by means ofa sub-process block 310 comprising heating the substrate to a desireddeposition temperature. For example, the substrate may be heated to asubstrate temperature of less than approximately 800° C., or less thanapproximately 700° C., or less than approximately 600° C., or less thanapproximately 5500° C., or less than approximately 500° C., or less thanapproximately 400° C., or less than approximately 300° C., or even lessthan approximately 200° C. In some embodiments of the disclosure, thesubstrate temperature during the exemplary atomic layer depositionprocess block 130 may be between 200° C. and 800° C., or between 300° C.and 700° C., or between 400° C. and 600° C., or between 500° C. and 550°C.

In addition, to achieving a desired deposition temperature, i.e., adesired substrate temperature, the exemplary atomic layer depositionprocess 130 may also regulate the pressure within the reaction chamberduring deposition to obtain desirable characteristics of the depositedmolybdenum metal film. For example, in some embodiments of thedisclosure, the exemplary atomic layer deposition process 130 may beperformed within a reaction chamber regulated to a reaction chamberpressure of less than 300 Torr, or less than 200 Torr, or less than 100Torr, or less than 50 Torr, or less than 25 Torr, or even less than 10Torr. In some embodiments, the pressure within the reaction chamberduring deposition may be regulated at a pressure between 10 Torr and 300Torr, or between 30 Torr and 80 Torr, or even equal to or greater than30 Torr.

Upon heating the substrate to a desired deposition temperature andregulating the pressure within the reaction chamber, the exemplaryatomic layer deposition process 130 may continue with a cyclicaldeposition phase 305 by means of a process block 320, which comprisescontacting the substrate with a first vapor phase reactant andparticularly, in some embodiments, contacting the substrate with a firstvapor phase reactant comprising a molybdenum halide precursor, i.e., themolybdenum precursor.

In some embodiments of the disclosure, the molybdenum halide precursormay comprise a molybdenum chloride precursor, a molybdenum iodideprecursor, or a molybdenum bromide precursor. For example, as anon-limiting example, the first vapor phase reactant may comprise amolybdenum chloride, such as, for example, molybdenum pentachloride(MoCl₅).

In some embodiments, the molybdenum halide precursor may comprise amolybdenum chalcogenide and in particular embodiments the molybdenumhalide precursor may comprise a molybdenum chalcogenide halide. Forexample, the molybdenum chalcogenide halide precursor may comprise amolybdenum oxyhalide selected from the group comprising: a molybdenumoxychloride, a molybdenum oxyiodide, or a molybdenum oxybromide. Inparticular embodiments of the disclosure, the molybdenum precursor maycomprise a molybdenum oxychloride, including, but not limited to,molybdenum (IV) dichloride dioxide (MoO₂Cl₂).

In some embodiments of the disclosure, contacting the substrate with afirst vapor phase reactant comprising a molybdenum halide precursor maycomprise contacting the molybdenum halide precursor to the substrate fora time period of between about 0.1 seconds and about 60 seconds, betweenabout 0.1 seconds and about 10 seconds, or between about 0.5 seconds andabout 5.0 seconds. In addition, during the contacting of the substratewith the molybdenum halide precursor, the flow rate of the molybdenumhalide precursor may be less than 1000 sccm, or less than 500 sccm, orless than 100 sccm, or less than 10 sccm, or even less than 1 sccm. Inaddition, during the contacting of substrate with the molybdenum halideprecursor the flow rate of the molybdenum precursor may range from about1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500sccm.

The exemplary atomic layer deposition process 130 for deposition amolybdenum metal film directly on the nucleation film as illustrated byprocess block 130 of FIG. 3 may continue by purging the reactionchamber. For example, excess first vapor phase reactant and reactionbyproducts (if any) may be removed from the surface of the substrate,e.g., by pumping with an inert gas. In some embodiments of thedisclosure, the purge process may comprise a purge cycle wherein thesubstrate surface is purged for a time period of less than approximately5.0 seconds, or less than approximately 3.0 seconds, or even less thanapproximately 2.0 seconds. Excess first vapor phase reactant, such as,for example, excess molybdenum precursor and any possible reactionbyproducts may be removed with the aid of a vacuum, generated by apumping system in fluid communication with the reaction chamber.

Upon purging the reaction chamber with a purge cycle the exemplaryatomic layer deposition process block 130 may continue with a secondstage of the cyclical deposition phase 305 by means of a process block330 which comprises contacting the substrate with a second vapor phasereactant, and particularly contacting the substrate with a second vaporphase reactant comprising a reducing agent precursor (“the reducingprecursor”).

In some embodiments of the disclosure, the reducing agent precursor maycomprise at least one of forming gas (H₂+N₂), ammonia (NH₃), hydrazine(N₂H₄), an alkyl-hydrazine (e.g., tertiary butyl hydrazine (C₄H₁₂N₂)),molecular hydrogen (H₂), hydrogen atoms (H), a hydrogen plasma, hydrogenradicals, hydrogen excited species, an alcohol, an aldehyde, acarboxylic acid, a borane, or an amine. In further embodiments, thereducing agent precursor may comprise at least one of silane (SiH₄),disilane (Si₂H₆), trisilane (Si₃H₈), germane (GeH₄), digermane (Ge₂H₆),borane (BH₃), or diborane (B₂H₆). In particular embodiments of thedisclosure, the reducing agent precursor may comprise molecular hydrogen(H).

In some embodiments of the disclosure, contacting the substrate with thereducing agent precursor may comprise contacting the substrate with thereducing agent precursor for a time period of between about 0.01 secondsand about 180 seconds, between about 0.05 seconds and about 60 seconds,or between about 0.1 seconds and about 10.0 seconds. In addition, duringthe contacting of the substrate with the reducing agent precursorsubstrate, the flow rate of the reducing agent precursor may be lessthan 30 slm, or less than 15 slm, or less than 10 slm, or less than 5slm, or less than 1 slm, or even less than 0.1 slm. In addition, duringthe contacting of the substrate with the reducing agent precursor to thesubstrate the flow rate of the reducing agent precursor may range fromabout 0.1 to 30 slm, from about 5 to 15 slm, or equal to or greater than10 slm.

Upon contacting the substrate with the reducing agent precursor, theexemplary process block 130 for depositing a molybdenum metal filmdirectly on a nucleation film may proceed by purging the reactionchamber. For example, excess reducing agent precursor and reactionbyproducts (if any) may be removed from the surface of the substrate,e.g., by pumping whilst flowing an inert gas. In some embodiments of thedisclosure, the purge process may comprise purging the substrate surfacefor a time period of between approximately 0.1 seconds and approximately10 seconds, or between approximately 0.5 seconds and approximately 3seconds, or even between approximately 1 second and 2 seconds.

Upon completion of the purge of the second vapor phase reactant, i.e.,the reducing agent precursor (and any reaction byproducts) from thereaction chamber, the cyclic deposition phase 305 of exemplary atomiclayer deposition process block 130 may continue with a decision gate340, wherein the decision gate 340 is dependent on the thickness of themolybdenum metal film deposited. For example, if the molybdenum metalfilm is deposited at an insufficient thickness for a desired deviceapplication, then the cyclical deposition phase 305 may be repeated byreturning to the process block 320 and continuing through a furtherdeposition cycle, wherein a unit deposition cycle may comprisecontacting the substrate with a molybdenum halide precursor (processblock 320), purging the reaction chamber, contacting the substrate witha reducing agent precursor (process block 330), and again purging thereaction chamber. A unit deposition cycle of cyclical deposition phase305 may be repeated one or more times until a desired thickness of amolybdenum metal film is deposited over the substrate and particularlydirectly on a nucleation film. Once the molybdenum metal film has beendeposited to the desired thickness the exemplary atomic layer depositionprocess block 130 may exit via a process block 350 and the substratecomprising a dielectric surface, with the molybdenum metal filmdeposited thereon, may be subjected to further processing for theformation of a device structure. For example, the exemplary process 100of FIG. 1 may proceed with the process block 140 wherein the processexits and the substrate with the molybdenum metal film disposed thereonmay be subjected to further semiconductor process to finalize thesemiconductor device structure.

It should be appreciated that in some embodiments of the disclosure, theorder of contacting of the substrate with the first vapor phase reactant(e.g., the molybdenum precursor) and the second vapor phase reactant(e.g., the reducing precursor) may be such that the substrate is firstcontacted with the second vapor phase reactant followed by the firstvapor phase reactant. In addition, in some embodiments, the cyclicaldeposition phase 305 of exemplary process block 130 may comprisecontacting the substrate with the first vapor phase reactant one or moretimes prior to contacting the substrate with the second vapor phasereactant one or more times. In addition, in some embodiments, thecyclical deposition phase 305 of exemplary process block 130 maycomprise contacting the substrate with the second vapor phase reactantone or more times prior to contacting the substrate with the first vaporphase reactant one or more times.

In some embodiments the cyclical deposition process utilized for thedeposition of the molybdenum metal film directly on a nucleation may bea hybrid ALD/CVD or a cyclical CVD process, as previously describedherein.

The molybdenum metal films deposited by the methods disclosed herein maybe continuous films. In some embodiments, the molybdenum metal film maybe continuous at a thickness below approximately 100 Angstroms, or belowapproximately 60 Angstroms, or below approximately 50 Angstroms, orbelow approximately 40 Angstroms, or below approximately 30 Angstroms,or below approximately 20 Angstroms, or below approximately 10Angstroms, or even below approximately 5 Angstroms. The continuityreferred to herein can be physical continuity or electrical continuity.In some embodiments of the disclosure the thickness at which a materialfilm may be physically continuous may not be the same as the thicknessat which a film is electrically continuous, and vice versa.

In some embodiments of the disclosure, the molybdenum metal films formedaccording to the embodiments of the disclosure, may have a thicknessfrom about 20 Angstroms to about 250 Angstroms, or about 50 Angstroms toabout 200 Angstroms, or even about 100 Angstroms to about 150 Angstroms.In some embodiments, the molybdenum metal films deposited according tosome of the embodiments described herein may have a thickness greaterthan about 20 Angstroms, or greater than about 30 Angstroms, or greaterthan about 40 Angstroms, or greater than about 50 Angstroms, or greaterthan about 60 Angstroms, or greater than about 100 Angstroms, or greaterthan about 250 Angstroms, or greater than about 500 Angstroms, orgreater. In some embodiments the molybdenum metal films depositedaccording to some of the embodiments described herein may have athickness of less than about 250 Angstroms, or less than about 100Angstroms, or less than about 50 Angstroms, or less than about 25Angstroms, or less than about 10 Angstroms, or even less than about 5Angstroms. In some embodiments, the molybdenum metal film disposed overa dielectric surface utilizing an intermediate nucleation film may havea thickness between approximately 100 Angstroms and 250 Angstroms.

In some embodiments of the disclosure, the molybdenum metal film may bedeposited over a dielectric surface utilizing an intermediate nucleationfilm such that the molybdenum metal film may comprise a crystallinefilm. In some embodiments, the molybdenum metal film may comprise apolycrystalline film wherein the plurality of crystalline grainscomprising the polycrystalline molybdenum metal film may have a grainsize greater than 100 Angstroms, or greater than 200 Angstroms, or evengreater than 250 Angstroms. In some embodiments, the crystallinestructure of the crystalline molybdenum metal film may comprise a bodycentered cubic structure.

In some embodiments of the disclosure, the molybdenum metal film may bedeposited over a dielectric surface with one or more high aspect ratiofeatures, including vertical high aspect ratio features and/orhorizontal high aspect ratio features.

For example, FIG. 4C illustrates a semiconductor device structure 410which comprises a dielectric material 402 with a vertical high aspectratio feature 404, wherein the aspect ratio (height:width) may begreater than 2:1, or greater than 5:1, or greater than 10:1, or greaterthan 25:1, or greater than 50:1, or even greater than 100:1, wherein inthis particular example “greater than” refer to a greater height of thegap feature. The deposition methods disclosure herein may be utilized todeposit a molybdenum metal film over the surface of the vertical highaspect ratio gap feature 404, as illustrated by a molybdenum metal film412. In some embodiments, the step coverage of the molybdenum metal filmover the vertical high aspect ratio dielectric gap feature may be equalto or greater than about 50%, or greater than about 80%, or greater thanabout 90%, or greater than about 95%, or greater than about 98%, orabout 99% or greater.

As a non-limiting example, the semiconductor device structure 410 mayrepresent a partially fabricated CMOS logic device wherein thedielectric material 402 may comprise an interlayer dielectric and themolybdenum metal film 412 may comprise a metal gap-fill for providingelectrical connection to one or more transistor structures (not shown).As illustrated in FIG. 4A, the molybdenum metal film 406 is in directcontact with the nucleation film 404 which is in turn disposed directlyon the dielectric material 402, i.e., without the need for anintermediate barrier layer material, thereby reducing the overalleffective electrical resistivity of the semiconductor device structure410.

In some embodiments, the molybdenum metal film 412 may be comprise agap-fill metallization and the molybdenum metal film 412 may fill thegap features, i.e., the vertical high aspect ratio gap feature 404,without the formation of a seam, wherein a seam may refer to a line orone or more voids formed by the abutment of edges formed in a gap fillmaterial, and the seam can be confirmed by using scanning transmissionelectron microscopy (STEM) or transmission electron microscopy (TEM),wherein if observations reveal a clear vertical line or one or morevertical voids in the gap fill material, a seam is present.

As a further non-limiting example, FIG. 5C illustrates a semiconductordevice structure 510 which comprises a dielectric material 502 with oneor more horizontal high aspect ratio gap features 504, wherein theaspect ratio (height:width) may be greater than 1:2, or greater than1:5, or greater than 1:10, or greater than 1:25, or greater than 1:50,or even greater than 1:100, wherein this example the term “greater than”refers to a great width of the one or more gap features. The depositionmethods disclosure herein may be utilized to deposit a molybdenum metalfilm 512 over the surface of the horizontal high aspect ratio gapfeature 504 utilizing an intermediate nucleation film 506. In someembodiments, the step coverage of the molybdenum metal film disposedover the horizontal high aspect ratio dielectric gap feature may beequal to or greater than about 50%, or greater than about 80%, orgreater than about 90%, or greater than about 95%, or greater than about98%, or about 99% or greater.

As a non-limiting example embodiment, the semiconductor device structure510 may represent a portion of a partially fabricated memory devicewherein the dielectric material 502 may comprise an aluminum oxide(Al₂O₃) and the molybdenum metal film 512 may comprise at least aportion of a metal gate structure.

As with the vertical gap-fill processes, the molybdenum metal film 512(of FIG. 5C) may be utilized as a gap-fill metallization for horizontalhigh aspect ratio features without the formation of a seam, aspreviously described.

In some embodiments of the disclosure, the molybdenum metal filmsdeposited directly on a nucleation film disposed directly on adielectric surface may comprise low electrical resistivity molybdenummetal films. In some embodiments, molybdenum metal films deposited overa dielectric surface utilizing an intermediate nucleation film may havea lower electrical resistivity than molybdenum films deposited directlyon a dielectric surface, i.e., without any intermediate nucleation film.For example, in some embodiments, the molybdenum metal films of thecurrent disclosure may have an electrical resistivity of less than 3000μΩ-cm, or less than 1000 μΩ-cm, or less than 500 μΩ-cm, or less than 200μΩ-cm, or less than 100 μΩ-cm, or less than 50 μΩ-cm, or less than 25μΩ-cm, or less than 15 μΩ-cm, or even less than 10 μΩ-cm. As anon-limiting example, a molybdenum metal film may be deposited over asurface of a dielectric material utilizing an intermediate nucleationfilm to a molybdenum metal film thickness of approximately less than 60Angstroms and the molybdenum metal film may exhibit an electricalresistivity of less than 40 μΩ-cm, or less than 35 μΩ-cm, or even lessthan 30 μΩ-cm.

In addition to improving the electrical resistivity of molybdenum metalfilms, the deposition of an intermediate nucleation film may alsoimprove the surface roughness of the deposited molybdenum metal films.For example, FIG. 6 demonstrates the r.m.s. surface roughness (R_(a)) inAngstroms for two exemplary 60 Angstrom thick molybdenum metal films.The molybdenum metal film denoted by label 600 was deposited directly onan aluminum oxide (Al₂O₃) dielectric surface and has a correspondingr.m.s. surface roughness (R_(a)) of approximately 7.3 Angstroms. Themolybdenum metal film denoted by label 602 was deposited directly on a 4Angstrom thick silicon nitride nucleation film disposed directly on analuminum oxide (Al₂O₃) dielectric surface and has a corresponding r.m.s.surface roughness (R_(a)) of approximately 3.3 Angstroms. It should benoted that the r.m.s. surface roughness (R_(a)) of molybdenum metalfilms may be determined utilizing atomic force microscopy, e.g., over asurface area of 1 micron×1 micron.

Therefore, the use of intermediate nucleation films greatly improves thesurface roughness of the molybdenum metal film, for example, in someembodiments, the r.m.s. surface roughness of the molybdenum metal filmsdeposited over a dielectric surface utilizing an intermediate nucleationfilm may have a r.m.s. surface roughness (R_(a)) of less than 5Angstroms, or less than 4 Angstroms, or less than 3 Angstroms, or evenless than 2 Angstroms. In some embodiments, the r.m.s. surface roughness(R_(a)) may be expressed as the percentage roughness of the total filmthickness. For example, in some embodiments the r.m.s. surface roughness(Ra) may be less than 10 percent, or less than 5 percent, or less 3percent, or even less than 1 percent of the total thickness of themolybdenum metal film.

In some embodiments of the disclosure, the methods of depositing amolybdenum metal film over a dielectric surface utilizing anintermediate nucleation film may further comprise depositing amolybdenum metal film with a low atomic percentage (atomic-%) ofimpurities. For example, the molybdenum metal films of the currentdisclosure may comprise an impurity concentration of less than 5atomic-%, or less than 2 atomic-%, or even less than 1 atomic-%. In someembodiments, the impurities disposed within the molybdenum metal filmmay comprise at least oxygen and chlorine.

The embodiments of the current disclosure may also provide semiconductordevice structures including molybdenum metal films. In some embodiments,the semiconductor device structures may comprise: a substrate comprisinga dielectric surface; a nucleation film disposed directly on thedielectric surface; and a molybdenum metal film disposed directly on thenucleation film. As non-limiting examples, semiconductor devicestructure 410 (of FIG. 4C) and semiconductor device structure 510 (ofFIG. 5C) comprise a dielectric substrate 402/502, the dielectricsubstrate comprising a dielectric surface. Disposed directly on thedielectric substrate 402 is a nucleation film 406/506, and disposeddirectly on the nucleation film 406/506 is a molybdenum metal film412/512. Therefore, in some embodiments, the nucleation 406/506 isdisposed directly between a molybdenum metal film 412/512 and adielectric material 402/502.

In some embodiments, the nucleation film 406/506 may comprise acontinuous film, whereas in alternative embodiments, the nucleation film406′/506′ may comprise a discontinuous film. In some embodiments, thecontinuous nucleation film 406/506 may a thickness of less than 20Angstroms, or less than 10 Angstroms, or less than 5 Angstroms, or evenless than 3 Angstroms. In some embodiments, the discontinuous nucleationfilm 406′/506′ may have a thickness of less than 20 Angstroms, or lessthan 10 Angstroms, or less than 5 Angstroms, or even less than 3Angstroms.

In some embodiments, the nucleation film 406/506 may comprise a compoundmaterial and in particular embodiments the nucleation film 406/506 maycomprise a binary compound material, such as, for example, a siliconbinary compound material or a molybdenum binary compound material. Insome embodiments, the nucleation film 406/506 may comprise a ternarycompound material, such as, for example, a silicon ternary material, ora molybdenum ternary material.

As non-limiting examples, a silicon binary compound material maycomprise at least one of a silicon nitride, a silicon carbide, or asilicon oxide. As further non-limiting examples, a molybdenum binarycompound material may comprise at least one of a molybdenum nitride, amolybdenum carbide, a molybdenum oxide, or a molybdenum silicide.

In some embodiments, the molybdenum metal films 412/512 may becrystalline and have an impurity concentration of less than 5 atomic-%,or less than 2 atomic-%, or even less than 1 atomic-%. In addition, themolybdenum metal films 412/512 may have an electrical resistivity ofless than 40 μΩ-cm at a thickness of less than 60 Angstroms.

In some embodiments, the molybdenum metal films 412/512 may have ar.m.s. surface roughness (R_(a)) of less than 5 Angstroms, or less than4 Angstroms, or less than 3 Angstroms, or even less than 2 Angstroms. Insome embodiments, the r.m.s. surface roughness (R_(a)) may be expressedas the percentage roughness of the total film thickness. For example, insome embodiments the r.m.s. surface roughness (Ra) may be less than 10percent, or less than 5 percent, or less 3 percent, or even less than 1percent of the total thickness of the molybdenum metal film. The lowsurface roughness of the molybdenum metal films 412/512 may enable themolybdenum metal films to fill one or more gap features disposed in andor on a substrate, such as vertical gap feature 404 and/or horizontalgap feature 504, without the formation of a seam, as illustrated bymolybdenum metal films 412 and 512.

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention, which is defined by the appendedclaims and their legal equivalents. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to those shown anddescribed herein, such as alternative useful combination of the elementsdescribed, may become apparent to those skilled in the art from thedescription. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

What is claimed is:
 1. A method for depositing a molybdenum metal filmover a dielectric surface of a substrate by a cyclical depositionprocess, the method comprising: providing a substrate comprising adielectric surface into a reaction chamber; depositing a nucleation filmcomprising a molybdenum compound material directly on the dielectricsurface, wherein depositing the nucleation film comprises performing atleast one unit cycle of a cyclical deposition process, wherein a unitcycle comprises: contacting the substrate with a first vapor phasereactant comprising a molybdenum precursor; and contacting the substratewith a second vapor phase reactant comprising at least one of a nitrogenprecursor, an oxygen precursor, or a carbon precursor; and depositing amolybdenum metal film directly on the nucleation film, whereindepositing the molybdenum metal film comprises: contacting the substratewith a first vapor phase reactant comprising a molybdenum halideprecursor; and contacting the substrate with a second vapor phasereactant comprising a reducing agent precursor.
 2. The method of claim1, wherein the second vapor phase reactant comprises at least one of anoxygen precursor and a carbon precursor.
 3. The method of claim 1,wherein the molybdenum compound material comprises a molybdenum binarycompound material.
 4. The method of claim 3, wherein the molybdenumbinary compound material comprises at least one of a molybdenum nitride,a molybdenum carbide, or a molybdenum oxide.
 5. The method of claim 1,wherein the molybdenum halide comprises a molybdenum chalcogenidehalide.
 6. The method of claim 5, wherein the molybdenum chalcogenidehalide comprises a molybdenum oxyhalide selected from the groupcomprising: a molybdenum oxychloride, a molybdenum oxyiodide, or amolybdenum oxybromide.
 7. The method of claim 6, wherein the molybdenumoxychloride comprises molybdenum (IV) dichloride dioxide (MoO₂Cl₂). 8.The method of claim 1, wherein the molybdenum metal film is acrystalline film.
 9. The method of claim 1, wherein the reducing agentprecursor comprises at least one of forming gas (H₂ and N₂), ammonia(NH₃), hydrazine (N₂H₄), an alkyl-hydrazine, an alcohol, an aldehyde, acarboxylic acid, a borane, and an amine.
 10. The method of claim 1,wherein the reducing agent precursor comprises at least one of silane(SiH₄), disilane (Si₂H₆), trisilane (Si₃H₈), germane (GeH₄), digermane(Ge₂H₆), borane (BH₃), and diborane (B₂H₆).
 11. The method of claim 1,wherein the reducing agent precursor comprises hydrogen excited species.12. The method of claim 1, wherein the molybdenum metal film has ar.m.s. surface roughness (Ra) of less than 5 percent of the totalthickness of the molybdenum metal film.
 13. The method of claim 1,wherein the molybdenum compound material comprises a molybdenum ternarycompound material.
 14. A semiconductor device structure formed accordingto the method of claim 1, the semiconductor device structure comprising:the substrate comprising the dielectric surface; the nucleation filmdisposed directly on the dielectric surface; and the molybdenum metalfilm disposed directly on the nucleation film.
 15. The semiconductordevice structure of claim 14, wherein a resistivity of the molybdenummetal film is less than 3000 μΩ-cm.
 16. The semiconductor devicestructure of claim 14, wherein the nucleation film is a discontinuousfilm.
 17. The semiconductor device structure of claim 14, wherein themolybdenum compound material comprises at least one of a molybdenumnitride, a molybdenum carbide, a molybdenum oxide, or a molybdenumsilicide.
 18. The semiconductor device structure of claim 14, whereinthe molybdenum metal film has an electrical resistivity of less than 40μΩ-cm at a thickness of less than 60 Angstroms.
 19. The semiconductordevice structure of claim 14, wherein the molybdenum metal film is acrystalline film.
 20. The semiconductor device structure of claim 14,wherein the molybdenum metal film has a r.m.s. surface roughness (R_(a))of less than 5 percent of the total thickness of the molybdenum metalfilm.